CSC/ECE 517 Fall 2010/ch7 7e ab

Protected Variations Pattern

7e. Protected Variations pattern. This is one of the GRASP patterns. Wikipedia: The Protected Variations pattern protects elements from the variations on other elements (objects, systems, subsystems) by wrapping the focus of instability with an interface and using polymorphism to create various implementations of this interface. Describe the pattern, and give examples of its use.

The Protected Variations pattern is one of the GRASP design patterns.

Section 3

http://web.cs.wpi.edu/~gpollice/cs4233-a05/CourseNotes/maps/class4/ProtectedVariations.html

http://en.wikipedia.org/wiki/GRASP_(object-oriented_design)#Protected_Variations

http://www.objectsbydesign.com/books/larman_notes/6-DesignAndImplementationTechniques.html

Originality. Chapter is not constructed by copy-and-paste, but rather is the writer's own work. Nor does it duplicate the organization of Wikipedia's article, or any other description of the topic. Rather, it should be presented in a way that differs from each of the sources.

Clarity. The language should be simple and basic. Sentences should be short enough to be understood by a student in this class without rereading. Jargon should be avoided, except for technical terms that are introduced before being used. For a more technical treatment, the reader should be referred to appropriate sources.

Coverage. All relevant material should be discussed, at about the same level of detail. If it is too involved, it is OK to reference external sources, but the entire chapter should not consist of references. Earlier sections should not be covered in more depth than later sections.

Organization. The chapter should begin with an overview suitable for readers who are new to the topic, and proceed from simpler material to more involved. The progression should be logical, and should not jump from one topic to another without transition.

Definitions. Definitions should be clear and concise, and should be supported by explanations or examples. Definitions should be just that--not descriptions. Definitions should should be composed by the author, not taken from other textbooks.

Examples. Examples should be clear, succinct, and unambiguous. Diagrams and realistic examples are encouraged, but diagrams need to be explained with accompanying text.

Citations. All major concepts should have citations to more detailed treatments. Citations should include a good mix of sources, such as Web sites, scientific papers, and books. Citations should be in a common format, such as ACM reference format; do not use just a Web link without any title or author.

Diagrams. If the coverage of this topic would benefit from diagrams, are sufficient diagrams included? Are they easily understandable and well explained?

Flow. Chapters should build on--and reference--earlier chapters. Coverage in this chapter should not duplicate earlier chapters, but use hyperlinks to refer to those earlier sections.

Accuracy. Is the information in this chapter consistent with other descriptions of the same material? Can any errors be identified? Is information purported to be factual indeed a matter of fact rather than opinion?